[A] a low-relief non-constructional plain formed through fluvial erosion

[B] an extensive plain formed in a desert by the coalescence of pediments

[C] an area of low-lying ground adjacent to a river, formed mainly of river sediments

[D] a landscape formed from the dissolution of soluble rocks such as limestone

Answer: [A] a low-relief non-constructional plain formed through fluvial erosion

Peneplains are formed by wearing down of land due to weathering and erosion. A peneplain is a featureless plain formed due to fluvial erosion. Some occasional raised areas which survive due to high resistance to erosion are called monad nocks found in peneplains.